The purpose of this project is to design and perform in-vivo testing of an implantable tissue culture system. There is evidence to suggest that control of diabetes with insulin does not prevent microangiopathic changes. It is felt that continuous control of glucose levels as normally done by pancreatic B-islet cells can prevent the above mentioned changes. There is interest in developing a system where pancreatic B-islet cells can be grown in a chamber that is perfused with arterial blood. These cells are actually separated from the blood path by a microporous membrane, across which glucose diffuses. Sensing the level of glucose, the cells then release an appropriate amount of insulin that then diffuses across the membrane back into the blood stream. Perhaps a more general use of this system in research would be the ability to grow previously difficult to grow cells, and if desired monitor the effects of their metabolic products on the animal while keeping the cells separated in a growth chamber.